confusing code....whats the point of this construct ?

[Nicholas Krause]

On March 11, 2015 2:37:32 PM EDT, Jeff Haran <Jeff.Haran at citrix.com> wrote:
>-----Original Message-----
>From: kernelnewbies-bounces at kernelnewbies.org
>[mailto:kernelnewbies-bounces at kernelnewbies.org] On Behalf Of
>Valdis.Kletnieks at vt.edu
>Sent: Wednesday, March 11, 2015 10:00 AM
>To: Nicholas Mc Guire
>Cc: Bj??rn Mork; kernelnewbies at kernelnewbies.org
>Subject: Re: confusing code....whats the point of this construct ?
>
>On Wed, 11 Mar 2015 17:46:56 +0100, Nicholas Mc Guire said:
>
>> ret = ({ long __ret = (5*250);
>>         do { _cond_resched(); } while (0);
>>  	if (!({
>> 		bool __cond = (({
>
>>Gaak.
>>
>>         ret = wait_event_timeout(mgr->tx_waitq,
>>                                  check_txmsg_state(mgr, txmsg),
>>                                  (4 * HZ));
>
>>-EGADS - use of macro as a function violates the Principle of Least
>Surprise....
>>
>>I have to wonder how many other places we've got bugs waiting to
>happen because of this....
>
>I don't understand the problem here. The caller passes in a condition
>to be evaluated in a loop. Many times that condition is quite simple
>(e.g. a counter being non-zero). If it was a function the caller would
>have to pass in a pointer to a function that does the evaluation, as
>in:
>
>int bar;
>
>int foo(void)
>{
>	return bar;
>}
>
>...
>
>	wait_event_interruptible(..., foo, ...);
>
>Instead of the much simpler:
>
>	wait_event_interruptible(..., bar, ...);
>
>That latter seems easier to understand and require fewer instructions
>to be generated since there is no function call overhead.
>
>Jeff Haran
>
>
>
 Due to complaints about this code., I am requesting a vote for me to send in a patch fixing this terribly ugly code. Please let me know about your results for the
vote for me making a patch to fix this code. 
Nick 
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